Solenoid motor for fuel pumps



NOV. 25, 1930. w CARTER 1,782,407

SOLENOID ROTOR FOR FUEL PUMPS Original Filed Sept. 28 1925 57 MMQ W.

Patented Nov. 25, 1930 PATENT OFFICE WILLIAM C. CARTER, F FLINT,MICHIGAN SOLENOID MOTOR FOR FUEL PUMPS Original application filedSeptember 28, 1925, Serial No. 59,149 Divided and thisxapplication filedNovember 14, 1928. Serial N'o. 319,241.

The main object of my present invention is to provide a solenoid motorfor fuel pumps, that is equipped with an automatically-operating,intermittent switch whose contacts are held pressed tightly togetherduring one stroke of the pumping element by a means separate anddistinct from the magnetic attraction of the solenoid, and are separatedwith a quick break by a spring-actuated hammer in which energy is storedby the magnetic attraction of the solenoid during th said stroke of thepumping element.

The figure of the drawing is a vertical longitudinal sectional viewillustrating my improved motor and controlling switch combined with aliquid fuel pump Whose pumping element consists of a flexible diaphragm.

Referring to the drawing, A designates the diaphragm of the pump, whichis preferably composed of a plurality of layers 00 of fabric treated torender it impervious to water, gasoline and the like, without making itbrittle or inflexible. Said diaphragm is arranged in opposed relation toa rigid, cup-shaped member 1, so as to form a pumping chamber 2, and theperipheral edge portion of said diaphragm is combined with the member 1and an opposed clamping member 3 that tightly clamps or' grips the edgeof the diaphra m. \Vhen the pump is in operation the iaphragm A movestowards and away from the wall 1 of the pumping chamber, so as to drawliquid fuel into 'said pumping chamber from a source of supply, andthereafter force said fuel out of said chamber to an internal combustionengine or to a carburetor associated with such an engine. The pumping.

chamber 2 is connected by one or, more ports 4: with a valve passageway5 equipped with an inlet valve 6 and -a discharge valve 7 When the pumpis in operation liquid fuel is drawn from a source of supply through aconduit that is connected to aninlet 8 at the lower end of the valvepassageway 5 and is discharged through an oulet 8 at the upper end ofthe said passageway.

' The diaphragm A is fixed in one direction by a solenoid whichcomprises a coil B and a core composed of a movable core piece C and astationary core piece C, the movable core piece C being connected to thecentral portion of the diaphragm A in any suitable manner, as, forexample, by means of a screw or bolt 10, screwed into the core piece Cand arranged with its head in engagement with a clamping plate'll thatclamps the central portion of the diaphragm A against the core piece C.As thediaphragm is formed from fabric, there is some slack in samebetween the clamping plate 11 at the center of the diaphragm andthe-clamping member 3 that grips the peripheral edge of the diaphragm.In order to take up this slack and keep the diaphragm taut, a spring 9is arranged in engagement with the diaphragm at a point between theperipheral edge portion of the diaphragm and the central portion of thediaphragm that is clamped to the movable core piece C, said spring 9exerting a counteracting force on the diaphragm. Due to the fact thatthe movable member-C of the core is directly connected to the diaphragmA, the spring 9 constantly exerts pressure on the core piece C in adirection tending to move it away from the stationary score piece CT,and b as said spring 9 surrounds the core piece and is interposedbetween the diaphragm A and the opposed member 3 which forms an abutmentfor one end of the spring 9, it effectively prevents the diaphragm fromflopping back and forth in opposite directions to the pumping strokes,thereby preventing the diaphragm from making an objectionable noise whenthe pump isin operation and adding materially to the life of thediaphragm.

The coil B of the solenoid is arranged inside of a housing of magneticmaterial formed by the member 3 previously referred to and by asubstantially cup-shaped member '12 that is combined with the member 3,as as illustrated in the drawing. The spool on which the coil B of thesolenoid is wound preferably comprises a tubular portion 13 ofnon-magnetic material and a tubular portion 13 of magnetic material thatis connected to the housing member 3 and which is of suflici ent areatoinsure the fluxpassing freely from, 4 the flux field to the core whenthe solenoid & circuit is closed, thereby making is possible to operatethe pump with a relatively small the solenoid of the pump is providedwith two switches, one a manually-operated switch (not shown) that isclosed when the pump is in use, and the other anautomatically-operating, intermittent switch that opens and closes thesolenoid circuit intermittently so as to cause, the movable core piece Cto reciprocate, and thus actuate the diaphragm or pumping element A ofthe pump. Said intermittent switch may be of any preferred construction,but I prefer to equip the pump with a switch whose movable contactconsists of a revolubly mounted member of disk or annular form arrangedso that it will move into and out of engagement with two stationarycontacts, one of which is electrically connected with the coil of thesolenoid and the other being grounded. Said intermittent switch isarranged inside of a removable cap piece 12 on the end wall of thehousing of the solenoid'and comprises a revoluble member 14 of disk orannular form that constitutes the movable contact of the switch and twostationary contacts 15 and 15* arranged in spaced relation at one sideof the movable contact 14, one of said stationary contacts beingelectrically connected to the coil B of the solenoid and the otherstationary contact being grounded. The movable contact l-i is carried byan insulator or contact carrier 16 that is rotatably mounted on atubular member 17 which constitutes a housing for a spring 18 that holdsthe contacts of the intermittent switch closed when the solenoid isimparting a suction stroke to the diaphragm. Said insulator 16 is movedoutwardly or away from the stationary contacts 15 and 15 by means of atubular striking portion 19 on the hammer D which surrounds the springhousing 17, and said insulator 'is moved inwardly toward said stationarycontacts by means of a stop 20 on a rod 21 that is rigidly connectedwith the bolt or screw 10 in the movable core piece C. The contactcarrier or insulator 16 of the intermittent switch is capable of bodilymovement relatively to the hammer D and said hammer D is so constructedand arranged that it will impart a sharp blow to the insulator 16 in adirection to open the solenoid circuit with a quick break at the end ofthe suction stroke of the diaphragm A, In the pump herein illustratedthe hammer D is provided with a ifzsaw? center socket that houses aspring 22 that is stronger than the spring 18, said spring 22surrounding the rod 21 previously referred to. A washer 23 is mounted onsaid rod between one end of the spring 22 and a spring 2-1 that isstronger than the spring 22 and which is arranged so that it bearsagainst the screw or bolt 10 in the movable core piece C, the "spring 22being confined between the washer 23 and the inner end of the socket inthe hammer D that receives said spring. The striking portion 19 of thehammer surrounds the spring housing 17, and the inner end of said springhousing is arranged in opposed relation to a shoulder 25 on the hamlner. The hammer D is arranged to reciprocate freely inside of thestationary member .0 of the core and is provided with aradially-projecting flange'26 that is positioned between two'stationarystops 27 and 28 of cork or other relatively soft material that cmoperate with said flange to limit the movement of said hammer inopposite directions.

When the solenoid circuit is open the movablemember C of the core isheld spaced away from the stationary member C by the expansive force ofthe spring 9 and the movable contact 14 of the intermittent switch isheld in engagement with the stationary contacts 15 and 15 by thepressure which the.

stop :20 on the rod 21 exerts on the. spring housing 17 whose flange 17bears against the insulator 16 that carries said movable contact 14. henthe manually-operable switch of the solenoid circuit is closed, themovable member C of the core moves inwardly towards thes tationary coremember C and the hammer D which isfree to reciprocate relatively to thestationary core member C assumes the position shown in the drawing.

a The inward movement of the core member C. namely, movement to theright, looking at the drawing, imparts a. suction stroke to thediaphragm A and also builds up energy in the spring 22 of the hammer Dand in the stiil spring 24: that is arranged on the other side of thewasher 23, it being understood that the lgumner D is held at rest durinthe inward stroke of the core member by the magnetic attraction of thesolenoid. During this time, namely, when the solenoid is imparting asuction stroke to the diaphragm,

the contacts of the intermittent switch are held tightly together by theforce of the spring 18 which is under compression at this time. Thespring 18 expands when the stop on the rod 21-moves to the right, andthus exerts pressure onthe spring housing 17 in a direction to hold theflange 17 thereon in engagement with the insulator 16. At the time thecore member C starts to move inwardly, namely, to the right from theposition shown in the drawing, the space between the tapered surface onthe core member C and the inclined surface on the inner end of thehammer Dis less than the space between the tapered surface on the coremember C and the tapered surface on the core member C. The inwardmovement-of the core member C reduces the width of said spaces, and whenthe core me'mbenC reaches such as position that the washer 23 bearsagainst the inner end of the hammer D, part of the flux path becomesshort-ci'rcuited across the air gap or space between the tapered surfaceof the core member C and the inclined surface on the inner end of thehammer, due, of course, to the fact that said space or air gap is ofless width than the space or air gap between the tapered surface on thecore member C and the tapered surface of the core member C.Consequently, the

hammer D starts to move with the core mem-- ber C, thereby causing thepulling force of the solenoid to be reduced automatically to such anextent that the solenoidexerts practically the same pull on thediaphragm at the end of the suction stroke as it exertedon the diaphragmat the beginning of the suction stroke. In other words, by forming thehammer in such a manner that the inner end of same is separated from thetapered surface of the core member C by an air gap of less width thanthe air gap between the tapered surfaces of the core members C and C",

I preventthe pull of the solenoid on the dia- I phragm from building upprogressively as the core member C moves inwardly. This is highlydesirable, as it prevents the diaphragm from being operated at such ahigh speed that time enough is not provided to insure a full charge offuel entering the pumping chamber before the diaphragm starts to move inthe opposite direction, namely, to the left, under the influence of thespring 9. At the time the hammer starts to move with the core member C,the spring 24 and spring 22 are exerting a longitudinal thrust on thehammer D that is only slightly less than the force which holds the coremember C and hammer D together. Further inward movement of the coremember C reduces the air gap between the members C and C, therebycutting down the attraction power of the hammer D to such an extent thatthe spring 24- breaks it loose from the core member C, and the hammer Dthereafter moves outwardly under the influence of the spring 22, theshoulder 25on said hammer engaging the inner end of the spring housingand moving said housing longitudinally in a direction to relieve thepressure on the insulator 16 which carries the movable contact 14 of theintermittent switch. Thereafter, thestriking portion 19 of said hammerimparts a sudden blow to the insulator 16 and moves it out-' wardly awayfrom the stationary contact of the intermittent switch, thus causing thesolenoid circuit to be opened with a quick break. Immediately thereafterthe core piece C moves outwardly, or to the left back to the ment withthe contacts 15 and 15*, as shown in Y the drawing, and close thesolenoid circuit.

Having thus described my invention, what I claim as new and desire tosecure by Letters Patent is: v

1. In a motor, a solenoid having a movable core, an intermittentlyoperating switch for governing the energizing circuit of said solenoid,a spring for holding the contacts of said switch closed during thestroke of the core of the solenoid in one direction, *and a separatemeans of greater force for holding tion of the solenoid on the hammerand for causing said hammer to strike the contact carrier and separatethe contacts of said switch with a quick break.

3. In a motor, a solenoid, a switch for gov erning the energizingcircuit ot the solenoid, a hammer combined with the solenoid in such away that the magnetic attraction of the solenoid holds the hammer atrest durin part of the actuating stroke of the core oi the solenoid andis reduced near the end of the stroke, a spring for overcoming themagnetic attraction exerted by the solenoid on the hammer, anindependent spring for causing said hammer to separate the contacts ofsaid switchwith a quick break, and a third spring of less strength thanthe springs previously referred to arranged so as to hold the contactsof said switch closed during the actuating stroke of the solenoid core.

4. In a motor, a solenoid provided with a .core composed of a stationarymember and a movable member that are normally separated by an air gap, aswitch for governing the energized circuit of the solenoid, a springarranged so that it is normally active for holding the contacts of saidswitch closed,

said contacts open during the stroke of the core of the solenoid in theopposite direction.

a movable hammer of magnetic material arranged so that it remains atrest during the first portion of the actuatingstroke of the movable coremember, and a resilient actuat- 1ng means for causing said hammer toseparate the contacts of said switch with a quick break, arrangedso thatenergy will be stored in same by the actuating stroke of the movablecore member.

5. In a motor, a solenoid provided with a core composed of a stationarymember and a movable member, a switch for governing the energizingcircuit of the solenoid, a hammer for separating the contacts of saidswitch with a quick break, constructed of magnetic material and arrangedto reciprocate inside of the stationary member of the core of thesolenoid. two springs of different tension 'arranged between said hammerand the movable member of the core and adapted to be compressed by theactuating stroke of said member, a spring combined with said switch fornormally holding the contacts of same closed, and a means connected withthe movable member of the core and arranged to move with same forvarying the tension of said switch spring.

6. Ina motor, a solenoid, a switch for controlling the energizingcircuit of the sole noid, a reciprocating hammer for separating thecontacts of said switch with a. quick break, arranged so that it 's heldat rest by the magnetic attraction of he solenoid durmg a portion of theactuating stroke of the solenoid core, a resilient actuating means forsaid springv in which energyis stored during the actuating stroke ofsaid core, stops that co-operate with a part on said hammer to flimitthe movement of same, and a resilient means whose tension variesaccording to the position of t movable member of the core, for normallyholding the contacts of said switch closed.

' WILLI C. CARTER.

